Wild rice, the iconic grain that grows across much of the northern half of the state, is at the center of a contentious debate over mining and the environment.

A 40-year-old state law limits how much of a mining byproduct called "sulfate" can be discharged into wild rice producing waters. Prompted by mining industry concerns that the standard is too stringent, the state has been giving it another look and will release results of its two-year study Monday.

For members of the state's Indian tribes, wild rice is sacred.

Jim Northrup, who has harvested wild rice on Perch Lake on the Fond du Lac reservation for over half a century, said the grain called "manomin" in Ojibwe is a gift from the Creator that led his people to first settle here.

Jim NorthrupDan Kraker / MPR News

"The old stories said we'd move west until we came to a spot where food grew on the water," Northrup said. "And that perfectly describes manomin. It's become our identity now. It's who we are."

Wild rice is now part of all of Minnesota's identity. It's even the official state grain. The plant's significance helped lead to a 1973 state law to protect it from sulfate pollution, a form of sulfur that occurs naturally in the environment, that's also a byproduct of industrial activities like wastewater treatment and mining.

The law limits sulfate discharges into wild rice producing waters to 10 milligrams per liter during periods when the rice may be susceptible to damage. It's based on research done by John Moyle, a biologist for the Minnesota Department of Conservation in the 1930s and 40s that found that no large wild rice stands grew in waters high in sulfate.

But the standard went largely unenforced until 2010, when the Minnesota Pollution Control Agency began to ask mining companies to document wild rice plants in lakes and streams where they discharge wastewater. The following year the agency issued a permit that limited sulfate discharges at U.S. Steel's Keewatin Taconite operation, known as Keetac.

Nancy Schuldt, water resource policy director for the Fond du Lac Band of Lake Superior Chippewa, said high levels of sulfate have been measured in those waters, and wild rice stands are disappearing.

Harvesting wild riceDan Kraker / MPR News

"The poster child would be Sandy and Little Sandy lake, at the toe of the Minntac Tailings basin," she said. "A generation ago, band members from Grand Portage for instance, were having rice camps there, and there would be familial gatherings and it was a meeting place. And now there's no rice to harvest."

But mining companies and some northern Minnesota lawmakers questioned the science behind the standard.

In 2010 the Minnesota Chamber of Commerce sued to overturn it, although the case was eventually dismissed by the courts. Bills were introduced to weaken it. In the end, lawmakers set aside $1.5 million for a two-year study to determine whether the standard is scientifically valid. The results will be released later Monday.

"The study actually relies on multiple lines of investigation," said Shannon Lotthammer, director of the MPCA's environmental analysis and outcomes division. She said scientists have gathered more field data from northern Minnesota and have conducted experiments on wild rice plants in glass jars in the lab and in plants grown outside in plastic tubs, to try to learn exactly what effect sulfate has on the plants.

An important question is whether sulfate by itself is the main culprit, Lotthammer said.
Scientists theorize that hydrogen sulfide damages wild rice. In an oxygen-starved environment like the muck in wild rice lakes, bacteria essentially breathe in sulfate, and exhale hydrogen sulfide, which can be toxic to plants.

Bagging wild riceDan Kraker / MPR News

"It's sulfate then being converted into sulfide in the sediment, and the sulfide affecting the wild rice through the roots," explained Lotthammer.

The study's results should provide more clarity. But Lotthammer said it will take the MPCA until the end of February to answer a key question:
"Do we believe that there's a reason to support, a scientific basis to support a change to the standard, and if so, does it look like the standard should be higher or lower, based on this new information?"

The MPCA's decision is sure to be highly scrutinized, particularly by the mining industry.
"We just believe that a standard should be based on science, and that companies shouldn't be required to invest maybe hundreds of millions of dollars, until we have science backing up whatever the appropriate sulfate level is for a standard to protect wild rice," said Frank Ongaro, executive director of Minnesota Mining. The industry group represents copper-nickel mines like PolyMet, currently under environmental review.

PolyMet officials say they will meet the current standard.

Supporters of the law argue it is based on sound science. Under the federal Clean Water Act, the burden of proof is on MPCA to show scientific proof before changing the standard, said Paula Maccabee, an attorney for WaterLegacy, a group that opposes the PolyMet proposal.

Wild riceDan Kraker / MPR News

"I think that's what we're counting on, is that, our laws don't make it easy for political pressure to weaken water quality standards," she said.

The MPCA will analyze study results for the next two months. In April the agency will begin a rulemaking process to address any recommended changes to the wild rice standard, and to designate which waters are subject to the sulfate limits.